The regulation of locomotion and of affect by basal forebrain structures has engaged the efforts of neuroscientists for decades. The caudate- putamen and the nucleus accumbens are jointly referred to as the neostriatum and have been implicated as regulatory foci in the programmatic aspects of locomotion and disease states such as Parkinson's, depression and schizophrenia. In addition to dopamine, gamma-aminobutyric acid, acetylcholine and excitatory amino acids (namely, glutamate and aspartate), these brain areas contain high levels of neuropeptides, namely, enkephalins, tachykinins, dynorphin, neurotensin and cholecystokinin. The involvement of the neuropeptides in neostriatal function is at present poorly understood. My research addresses the problem of neuropeptide regulation and interactions in the neostriatum. Over the next few years, my laboratory will be engaged in characterizing the mode of action by which excitatory amino acids affect neuropeptide expression in the neostriatum. This is of vital importance because excitatory amino acids have been implicated in neurotoxic and neurodegenerative processes in the mammalian brain.